BRUSSELS (Reuters) - The European Union said on Thursday jail sentences handed down to three European feminist activists who staged a topless protest in Tunisia were too severe and urged the Islamist-led government to reform its laws on freedom of expression.

A Tunisian court sentenced one German and two French members of women's rights group Femen to four months in prison on Wednesday for indecency after they appeared topless in the capital last month.

Marguerite Stern and Pauline Hillier of France and Josephine Markmann of Germany were calling for the release of Tunisian feminist activist Amina Tyler, who has been in detention since mid-May.

"The EU is surprised by the severity of the judgment," a spokesman for EU foreign policy chief Catherine Ashton said.

"To ensure ... freedom of expression, the EU underlines the need to revise laws inherited from the previous regimes, which can be used to restrict it," Michael Mann said.

Tyler, a Femen member, caused a storm of controversy in Tunisia after she published topless photographs of herself on Facebook with the words "My body belongs to me and not the honor of others" written on her chest in Arabic.

The 18-year-old was demonstrating against the rising presence of hardline Islamist Salafists in Tunisia that has alarmed a secular elite who fear this could undermine individual freedoms, women's rights and democracy.

The topless protests have scandalized many in Tunisia, a Muslim country where public nudity is not socially or religiously acceptable.

Tyler was arrested in the town of Kairouan on May 19 after she wrote a feminist slogan on the wall of a mosque and tried to bare her breasts, on the same day that the radical Islamist Ansar al-Sharia group was due to hold a rally in the city.

Tunisia was the first country to be rocked by an "Arab Spring" uprising, inspiring similar revolutions in Egypt and Libya.

The new government is led by a moderate Islamist party, Ennahda.

Femen has staged protests across Europe, mainly against Russia's detention of the all-female Pussy Riot punk band last year.

(Reporting by Justyna Pawlak; Editing by Rex Merrifield and Raissa Kasolowsky)